Inadequate half-lives of therapeutics often necessitate their administration at high frequencies and/or higher doses, or the use of sustained release formulations, in order to maintain serum levels necessary for therapeutic effects. Yet, this is often associated with negative side effects. For example, frequent systemic injections present considerable discomfort to the subject, and pose a high risk of administration-related infections, and may require hospitalization or frequent visits to the hospital, in particular when the therapeutic is to be administered intravenously. Moreover, in long term treatments, daily intravenous injections can also lead to considerable side effects of tissue scarring and vascular pathologies caused by the repeated puncturing of vessels. Similar problems are known for all frequent systemic administrations of therapeutics, such as, for example, the administration of insulin to diabetics, or interferon drugs to patients suffering from multiple sclerosis. All these factors lead to a decrease in patient compliance and increased costs for the health system.
This application provides compounds that increase the serum half-life of various therapeutics, compounds having increased serum half-life, and methods for increasing the serum half-life of therapeutics. Such compounds and methods for increasing the serum half-life of therapeutics can be manufactured in a cost effective manner, possess desirable biophysical properties (e.g., Tm, substantially monomeric, or well-folded), and are of a size small enough to permit tissue penetration.